A new study suggesting that the dodo might have been moderately intelligent while also having an enhanced sense of smell challenges the common notion that the extinct bird of Mauritius was stupid. The findings are published in the Zoological Journal of the Linnean Society.

Skeleton cast and model of the dodo (based on modern research) at the Oxford University Museum of Natural History. Photo credits: Oxford University Museum of Natural History/ via Wikimedia Commons.

It is often said that the dodo (Raphus cucullatus) must have been a stupid creature. The bird, endemic to Mascarene island of the Indian Ocean, Mauritius, went extinct after being hunted down by Dutch settlers; it was last seen in 1662. The birds’ disappearance is also linked with the introduction of invasive species. They are said to have been easy prey because they showed no fear of humans, and were flightless, and thus helpless, but not necessarily stupid, says new study. The lead author of the paper, Eugenia Gold, from the American Museum of Natural History’s Richard Gilder Graduate School, says that the bird might have been dismissed as being dumb because it is now mostly known for it extinction. Regardless, so many features of its biology remains unknown.

The new findings provide invaluable insight into the little that can be grasped from the very rare specimens of the creature — they show that the size of the dodo’s brain relative to its body was equivalent to that of its closest living relative, the pigeon. The latter is known for its ability to be trained which requires a certain level of intelligence. This implies that the dodo was also probably endowed with similar attributes. Furthermore, it might also have had an enhanced sense of smell: this was deduced because of the presence of an enlarged olfactory bulb.

Gold analysed the dodo’s brain that she obtained from a skull preserved by the Natural History Museum of London. She used high-resolution computed tomography (CT) scan to delve into the organ. She simultaneously CT-scanned the skulls of pigeons of 7 different species. Using these findings, she constructed virtual brain endocasts to evaluate the size of the brain, and other features.

The brain was found to be neither too large nor too small. Rather, it was the right size given its body size. Furthermore, the comparison with other birds indicates that the dodos were likely to have had a similar intelligence level to that of the pigeons.

The observations also reveal a large olfactory bulb which is situated in the brain, and is associated with smelling. Birds’ brainpower would normally be focused on the sense of sight for them to be able to navigate through their environment (instead of having big olfactory bulbs, they have bigger optic lobes), and the enlarged olfactory bulb that has been discovered in the dodo is deemed unusual for the animal. But, then, the dodo, which was bound to the ground, maybe depended on its sense of smell for foraging purposes.

Another finding of the study is that the solitaire, another extinct bird which was endemic to Rodrigues, also had an enlarged olfactory bulb. The Rodrigues solitaire was also flightless, and was the closest relative of the dodo. This again suggests that the Earth-bound birds would use smell to locate food.

The findings bring to light a new facet of the dodo. Maybe, the slang term “dodo” meant to denote a stupid and dull-witted person is very much erroneous.